The present invention relates to a process for producing a coil for a magnetic recording head and to a coil obtained by this process. It is used in the field of magnetic recording, disk memories, tape unreeling devices, videoscopes, etc.
A magnetic recording head comprises an open magnetic circuit having an air gap and a coil surrounding a leg of the magnetic circuit. On writing, the passage of a current through the coil produces a leakage field at the air gap permitting the writing of information in a recording layer in the vicinity thereof. On reading, a magnetic flux variation from the recording layer induces, at the terminals of the coil, a potential difference constituting a reading signal.
A magnetic recording head coil generally comprises one or more conductive spirals arranged in different planes. In order to produce such a coil, a first conductive spiral is formed by deposition and then etching of a metal layer, followed by the deposition of an insulating layer on the assembly. This process is repeated for forming a second spiral on the insulating layer. The etching operations take place through masks and the two masks used are arranged in such a way that the two spirals are displaced from one another.
Such a procedure is more particularly described in the article by Y. NORO entitled "Fabrication of a multitrack thin-film head" published in the Journal of Applied Physics, Vol. 53, 3, March 1982, pp. 2611-2613.
Although such processes are satisfactory in certain respects, they are difficult to perform, particularly due to the double masking necessary for defining the coil. Thus, it is necessary to position the second mask with considerable accuracy with respect to the first, or more precisely with respect to the first spiral obtained.